背阔肌节段肌瓣一期修复晚期面瘫的应用解剖

目的 为联合应用背阔肌两块节段肌瓣一期动力矫正晚期面瘫表情肌功能提供解剖学依据.方法 解剖20具10%福尔马林固定的成人尸体共40侧背阔肌标本,醋酸乙酯血管灌注2具新鲜成人尸体共3侧背阔肌标本,观察肌外、肌内神经血管的分布特点.结果 ①92.5%的胸背神经分为内、外侧支;7.5%的胸背神经分为内、中、外侧支.胸背神经内、外侧支分叉点的坐标为(7.94±1.23)em、(3.71±1.68)cm,在该交角的中线区域,神经血管的数量相对较少.②背阔肌外侧肌瓣可以分为3～5个亚单位,内侧肌瓣可以分为2～4个亚单位.③肌内神经血管分支排列关系(由内向外),内侧节段100%为NVAV(神经、静脉、动脉、静脉),外侧节段85.0%为VAVN,其余15.0%为NVAV.④在神经蒂分支点外侧切断,第三段内侧肌瓣神经蒂平均达16 cm,第三或四段外侧肌瓣神经蒂平均达12 cm.结论 吻合血管神经的背阔肌双节段肌瓣移植可一期跨面修复晚期面瘫.     

Transverse splitting of the gracilis muscle free flap: Maximal use of a single muscle

The gracilis muscle, based on the dominant pedicle, has been used extensively for free tissue transfer. Recent studies have described the constant anatomy, ease of dissection, and low donor-site morbidity of the distal segmental gracilis free muscle flap. We present three cases of free distal segmental gracilis muscle transfer. In one case, the gracilis muscle was divided transversely into one proximally based and one distally based free flap and used for coverage of two separate wounds in a patient with bilateral open calcaneal fractures. In two cases, the preserved proximal gracilis was used as a reoperative free flap after failure of the initial distal segmental gracilis free muscle. With recent advances in microsurgery and ever-growing demands for low donor-site morbidity, it is important to ensure each free muscle flap harvested is used efficiently. Use of the free distal segmental gracilis muscle flap maximally uses one muscle while minimizing donor site morbidity and retaining the proximal muscle for future uses.     

The teres major muscle: an anatomic study of its use as a tendon transfer.

Eleven fresh-frozen cadaver shoulders were dissected to define the anatomy of the teres major muscle and tendon and to determine the muscle's potential for use as a tendon transfer to the humeral head. Of the 11 specimens, 7 had Mathes type II circulation. The primary and secondary pedicles, from the circumflex scapular artery, entered the muscle 4.1 cm and 0.5 cm from the scapula, respectively. The lower subscapular nerve entered 4.1 cm from the scapula. Mean tendon and muscle lengths were 2.0 and 11.8 cm, respectively. As a unipolar transfer, the tendon reached the greater tuberosity in all but 1 specimen. The bipolar transfer offered numerous theoretical possibilities. We believe that the teres major has an appropriate vascular supply and adequate length to make it suitable for tendon transfer to the humeral head.     

Reconstruction of elbow flexion by transposition of pedicled long head of triceps brachii muscle

A new technique of restored flexion in the elbow joint in an inveterate injury of the brachial plexus is described. The insertion of the long head of the triceps brachii muscle was transferred with an intact nervous and vascular supply to the anterior brachial region and sutured above the radial tuberosity with the insertion tendon of the biceps brachii muscle. The muscle strength three months after surgery according to the muscle test was 4-. Flexion in the elbow joint was possible up to 85 degrees. Extension in the elbow joint was preserved, the muscle strength was 3. Anatomical investigation revealed that the mean length of the nerve of the long head of the triceps was 5.5 cm, the number of terminal branches was 3-4, 70% of the vascular supply was from the brachial artery, the length of the vascular bundle was 3.6 cm. In 33% there was an additional neurovascular hilus which was 2-3 cm distally from the main hilus. The investigation confirms that the neurovascular pedicle of the long head of the triceps brachii muscle is sufficiently mobile and damage by traction during transposition of the insertion tendon is therefore not likely. Transfer of the long head of the triceps brachii muscle in inveterate injuries of the brachial plexus is a suitable alternative for reconstruction of nerves or transfer of other muscles to restore flexion in the elbow joint.     

A cadaver study on preserving peroneal nerves during ankle arthroscopy

BACKGROUND: Ankle arthroscopy is an important diagnostic and therapeutic procedure, but neurovascular injury remains a disadvantage. By understanding the anatomy of the superficial peroneal nerve (SPN) and deep peroneal nerve (DPN) the risk of nerve injury can be minimized. METHODS: Thirty-four lower limbs from 17 cadavers were dissected to find the safest anatomical points easily during arthroscopy. RESULTS: There was a single branch of the SPN in eight of 34 specimens (23.5%); type 1), two branches in 18 (52.9%; type 2), three branches in six (17.7%; type 3) and four branches in two specimens (5.9%; type 5) at the level of the talocrural (TC) joint. The closest SPN branch to lateral border of the TC joint was 14 +/- 8.4 mm. There was no branch of the SPN or DPN medial to the extensor hallucis longus tendon in any specimen. The DPN bifurcation was 6.5 mm proximal to the TC joint in a single specimen (2.9%) and 14.5 +/- 5.5 mm distal to TC joint in 26 specimens (76.5%). In four specimens (11.8%), the DPN bifurcation was at the same level with the TC joint. In three specimens (8.8%), there was no bifurcation of the DPN. CONCLUSIONS: From this study the anatomic landmarks defining the medial midline portal are safely away from the SPN and DPN and their respective branches. Clinical studies are needed to define its safety during ankle arthroscopy. CLINICAL RELEVANCE: This study proves that the medial midline portal is the best portal for the anterior arthroscopic procedures.     

Gracilis muscle in man]

This study is based upon the dissection of 84 gracilis muscles in 42 cadavers. It allowed to emphasize the following features: 1-The proximal insertion of the muscle is a strong tendinous lamina arising from the anterior aspect of the pubis and from the ischio-pubic branch; the distal insertion to the tibia is common to both the gracilis and the semi-tendinous muscles. 2-The distal tendon of the gracilis is tightly connected to the posterior branch of the internal saphenous nerve which crosses the muscle behind the medial femoral condyle. 3-The arterial supply (52 dissections) appears to be very rich, consisting in various pedicles entering the muscle by is lateral side. The main neurovascular bundle is issued from the profound vessels of the thigh, coming either from the adductors artery (73%), either from the medial circumflex artery (19.2%), either from both networks (7.7%). The site of penetration of the vessels in the muscle is remarkably constant. The remaining pedicles (2 to 4, one of which is quite constant at the musculotendinous junction) arise from the muscular branches of the femoral artery. 4-There is a good correlation between the measured length of the muscle and the distance between the superior aspect of the pubic arch and the medial epicondyle. A 0.37 corrective factor applied to this latter distance allows to determine the exact sit of penetration of the main neurovascular bundle in the muscle.     

Fiber length variability within the flexor carpi ulnaris and flexor carpi radialis muscles: implications for surgical tendon transfer

PURPOSE: The purpose of this study was to understand the detailed architectural properties of the human flexor carpi radialis (FCR) and flexor carpi ulnaris (FCU) muscles and their implications for tendon transfer surgery. METHODS: Muscle fiber length was measured in 6 separate regions of the FCU and FCR from 10 cadaveric specimens. Sarcomere length was measured by laser diffraction for normalization. Moment arms were estimated by measuring tendon excursion with respect to joint angle. The position of entry of the motor nerve branches into each muscle also was measured to establish limits for the safe length of muscle mobilization. RESULTS: Muscle fiber length varied significantly along both the FCU and FCR. Fiber length variability in the FCU was twice that of the FCR. Although the average fiber length for both muscles across all regions was similar (62.6 +/- 2.1 mm for the FCR and 63.1 +/- 4.0 mm for the FCU), the proximal fibers of the FCU were longer compared with the proximal fibers of the FCR and the distal fibers of the FCU were shorter compared with the distal fibers of the FCR. The 99% confidence interval for the second nerve branch entry into the muscles was located approximately 69 mm distal to the medial epicondyle for the FCU and approximately 73 mm distal for the FCR. CONCLUSIONS: These data show different designs of both the FCU and the FCR. The functional significance of fiber length variability is not clear but imply that, when used in tendon transfer, the properly mobilized FCU has a much greater excursion.     

Selective fascicular coaptation of free functioning gracilis transfer for restoration of independent thumb and finger flexion following Volkmann ischemic contracture

Children are prone to developing moderate to severe Volkmann ischemic contracture following a supracondylar fracture of the humerus or its treatment. Given the variable extent of forearm muscle damage, tendon transfers and tenodeses are often unavailable. To address these contractures, intensive hand therapy and a free functioning muscle transfer are required. Despite functional improvement following free muscle transplantation, reconstructed patients with severe Volkmann ischemic contracture tend to have persistent difficulty with fine motor activities owing to the losses of intrinsic muscle function and independence of thumb and finger flexion. The authors demonstrate how selective coaptation of separate fascicular territories of the gracilis nerve branches to the branches of the anterior interosseous nerve that innervate flexor pollicis longus and flexor digitorum profundus may be performed to establish a degree of independent thumb and finger flexion with a single free gracilis transfer. This technical refinement as well as its long-term outcomes in a series of three patients is presented.     

A modified longitudinally split segmental rectus femoris muscle flap transfer for facial reanimation: anatomic basis and clinical applications.

The present study was conducted to investigate the intra-muscular neurovascular anatomy and the intra-muscular tendon distribution of the rectus femoris muscle to reassess the reliability of technique of harvesting a longitudinally split segmental muscle flap, and to present our clinical experience on usefulness of the longitudinally split segmental rectus femoris muscle flap as a method for reconstruction of the paralysed face in a series of 25 patients. Twenty fresh cadavers were systemically injected with lead oxide, gelatin and water. Based on the anatomy of intra-muscular neurovascular structure in the rectus femoris muscle, 25 consecutive patients with established facial paralysis were treated by using a two-stage method combining neurovascular free-muscle transfer with cross-face nerve grafting. Follow-ups were 15-24 months. All of the 25 patients showed significantly improvement in the appearance of the oral commissure and oral competence. Satisfactory results of facial reanimation were obtained in 23 patients. Among these cases, near-natural facial expression was achieved. Recovery continued up to 2 years postoperatively. There were two cases having poor movement of transferred muscle 2 years postoperatively. No complications occurred in the donor site. In conclusion, the present study has demonstrated the suitability for subdivision of the segment muscle flap of the rectus femoris into two functional units with a common neurovascular pedicle. This series has further demonstrated the safety and reliability of using the rectus femoris muscle flap for facial reanimation.     

Anatomy and relationships of the suprascapular nerve: anatomical constraints to mobilization of the supraspinatus and infraspinatus muscles in the management of massive rotator-cuff tears.

Thirty-one shoulders in eighteen cadavera were dissected to allow study of the neurovascular anatomy of the rotator cuff and to help determine the limits of mobilization of the cuff for the repair of chronic massive retracted tears. The dissection demonstrated the diameter, length, and relationships of the suprascapular nerve and its branches and made clear the dangers of extensive mobilization and advancement of the supraspinatus and infraspinatus muscles. The suprascapular nerve ran an oblique course across the supraspinatus fossa, was relatively fixed on the floor of the fossa, and was tethered underneath the transverse scapular ligament. In twenty-six (84 per cent) of the thirty-one shoulders, there were no more than two motor branches to the supraspinatus muscle, and the first was always the larger of the two. In twenty-six (84 per cent) of the thirty-one shoulders, the first motor branch originated underneath the transverse scapular ligament or just distal to it. In one shoulder (3 per cent), the first motor branch passed over the ligament. The average distance from the origin of the long tendon of the biceps to the motor branches of the supraspinatus was three centimeters. In fifteen (48 per cent) of the thirty-one shoulders, the infraspinatus muscle had three or four motor branches of the same size. The average distance from the posterior rim of the glenoid to the motor branches of the infraspinatus muscle was two centimeters. The motor branches to the supraspinatus muscle were fewer, usually smaller, and significantly shorter than those to the infraspinatus muscle. The standard anterosuperior approach allowed only one centimeter of lateral advancement of either tendon and limited the ability of the surgeon to dissect safely beyond the neurovascular pedicle. The advancement technique of Debeyre et al., or a modification of that technique, permitted lateral advancement of each muscle of as much as three centimeters and was limited by tension in the motor branches of the suprascapular nerve. In some situations, the safe limit of advancement may be even less. We concluded that lateral advancement of the rotator cuff is limited anatomically and may place the neurovascular structures at risk.     

Segmental latissimus dorsi free flap: clinical applications

For 15 years, the latissimus dorsi muscle has enjoyed a consistent reputation with reconstructive surgeons as a reliable pedicle or free flap transferred with or without a skin island. Previous laboratory investigation has delineated the neurovascular intramuscular anatomy. The segmental latissimus transfer makes use of the intramuscular anatomy such that a lateral segment of the muscle is denervated and transferred with the thoracodorsal vascular pedicle while the medial segment of the muscle remains in situ innervated normally and perfused by the dorsal perforating branches of the ninth, tenth, and eleventh intercostal vessels. In this article we report our results using segmental free flap transfer of the latissimus dorsi muscle in 11 patients. Electromyographic studies have been performed more than a year postoperatively to document the function of the residual latissimus left in situ. Our clinical observations show that the segmental free transfer of the latissimus dorsi muscle can be accomplished with little risk in those situations not requiring the entire muscle, and that the portion of the muscle not transferred continues to function well and improves the contour of the back.     

Technique of harvesting the gracilis for free functioning muscle transplantation

In this article, we describe our technique and experience in harvesting the gracilis muscle for free functioning muscle transplantation (FFMT). The gracilis is the most commonly used muscle for FFMT. The main indication for gracilis FFMT is traumatic brachial plexus injury. Gracilis muscle has a class 2 vascular pedicle, with a dominant vascular pedicle originating from the profunda femoris vessels and a single motor nerve originating from the obturator nerve. During gracilis harvest, it is important to include the entire fascia around the muscle to ensure vascularity of the skin paddle and enhance muscle gliding in its new bed. Mobilization of the adductor longus allows tracing of the pedicle to its origin from the profunda femoris vessels, hence, achieving the maximum available length of the pedicle. Lengthening of gracilis tendon with a periosteal strip provides a free gracilis long enough to span the distance from the clavicle to the distal forearm. The main complications are related to the wound, and these include delayed healing, infection, and scar-related problems. The functional deficit after gracilis harvest is negligible.     

Biomechanical analysis of the brachioradialis as a donor in tendon transfer

Anatomic and biomechanical properties of the passive brachioradialis muscle were investigated to understand the limited excursion of this muscle seen during tendon transfer surgery. First, architectural measurements were performed on three fiber bundles obtained from four regions of the brachioradialis (10 specimens) chosen to represent the range of muscle fiber lengths across the brachioradialis. Next, in separate specimens (eight specimens), passive excursion was measured by securing the distal tendon stump to a servomotor. A constant load of 4.9 N was applied to the tendon, while the distal tendon was released from the surrounding tissue in 3-cm increments. Within the four regions studied, muscle fiber length varied significantly from 104.2 +/- 6.2 mm to 179.8 +/- 6.1 mm. As the brachioradialis was released, an average of 3 mm of mobility was obtained for each interval whereas for the succeeding three intervals, an average of 5.3 mm of mobility was obtained. This resulted in 22.2 +/- 2.3 mm of mobility when each specimen was fully released. These data show that there is no intrinsic muscle fiber length limitation to excursion, but that excursion is limited by other intermuscular connections to adjacent connective tissue and other muscles.     

The transverse gracilis musculocutaneous flap.

Through detailed anatomical study and latex injection of 24 cadaver legs, the blood supply to the skin overlying the gracilis muscle was examined. The proximal pedicle entered the gracilis muscle 10 +/- 2 cm below the pubic tubercle. The dissections identified both septocutaneous and musculocutaneous perforators from the proximal gracilis pedicle. These branches had a pronounced tendency to travel in a transverse direction, supplying the cutaneous territory over the adductor longus and sartorius anteriorly and extending for > 5 cm beyond the posterior margin of the gracilis muscle. This information led to a "new" transverse design of the gracilis musculocutaneous flap, such that the vascular perforators are invariably included in the cutaneous portion of the flap. In contrast, the traditional design, because of skin mobility, may allow elevation outside the skin territory of the muscle perforators.     

Anatomic evaluation of the subcoracoid pectoralis major transfer in human cadavers

Subcoracoid transfer of the pectoralis major has recently been described as a reconstruction for subscapularis insufficiency. The purpose of this study was to examine the surgically relevant anatomy of this transfer. The importance of understanding this anatomy was recently highlighted to us following our encounter with musculocutaneous neuropraxia in 2 patients after transfer of the entire pectoralis major, one deep to the musculocutaneous nerve. Dissections were performed on 20 fresh, whole human cadavers in which the entire pectoralis major muscle, medial and lateral pectoral nerves, and musculocutaneous nerve were explored and quantified. The relationship between the pectoralis major and the conjoined tendon was studied in situ and after simulated transfers. The medial and lateral pectoral nerves were located far medial to the pectoralis major tendon insertion and appeared to be safe from injury as long as surgical dissection remained lateral to the pectoris minor and less than 8.5 cm from the humeral insertion. Transfer of the pectoralis major superficial to the musculocutaneous nerve created less tension than transfer deep to the musculocutaneous nerve. Because proximal innervation of the coracobrachialis and short head of the biceps is not an uncommon occurrence, a split pectoralis major transfer, release of the proximal musculocutaneous branches, or debulking of the pectoralis major muscle belly may be required in some instances to prevent tension on the nerve. Because of the variability and location of the musculocutaneous nerve, it should always be visualized operatively. Transfer of the pectoralis major tendon lateral to the biceps tendon appeared to best restore the muscle length-tension relationship.     

Surgical anatomy of the gastrocnemius recession (Strayer procedure)

BACKGROUND: The Strayer procedure (gastrocnemius recession) is a treatment option for patients with clinically relevant gastrocnemius equinus contracture. The purpose of this study was to review the surgical anatomy of the Strayer procedure with specific reference to 1) the location of the sural nerve, and 2) the gastrocnemius tendon release point. METHODS: Forty consecutive Strayer procedures in 33 patients (15 males, 18 females) served as the study group. Recorded measurements included: 1) the location of the sural nerve relative to the deep fascia, 2) the distance from the medial border of the gastrocnemius tendon to the sural nerve, and 3) the distance from the distal end of the gastrocnemius muscle belly (identified by surface landmarks) to the actual release site. RESULTS: At the point of the gastrocnemius release, the sural nerve was located superficial to the fascia in 17/40 legs (42.5%) and deep to the fascia in 23/40 legs (57.5%). In five legs (12.5%), the nerve was directly applied to the gastrocnemius tendon and needed to be gently dissected off the tendon. The gastrocnemius release point was located an average of 18 mm distal (range, 20 mm proximal to 57 mm distal) to the surface landmark created by the distal extent of the gastrocnemius muscle belly. CONCLUSION: Knowledge of the relevant anatomy associated with the gastrocnemius recession should allow surgeons to minimize the rate of sural nerve injuries and improve cosmesis by decreasing the length of the surgical incision. A posteromedial incision that begins 2 cm distal to the gastrocnemius indentation and extends proximally will minimize the length of the incision required.     

Redefining the vascular anatomy of the peroneus brevis muscle flap

The peroneus brevis flap can be used as either proximally or distally based flap for coverage of small to medium‐sized defects in the lower leg. The purpose of this study was to clarify the vascular anatomy of the peroneus brevis muscle. An anatomical dissection was performed on 17 fixed adult cadaver lower legs. Altogether, 87 segmental branches (mean 5.1 ± 1.6 per leg) either from the fibular or anterior tibial artery to the muscle were identified. Sixty‐two were branches from the fibular artery (mean 3.4 ± 1.1 per fibular artery), whereas 25 (mean 1.4 ± 0.9 per anterior tibial artery) originated from the anterior tibial artery. The distance between the most distal vascular branch and the malleolar tip averaged 4.3 ± 0.6 cm. An axial vascular bundle to the muscle could be identified in all cadavers; in one leg two axial supplying vessels were found. Their average length was 5.5 ± 2.4 cm and the average arterial diameter was 1.1 ± 0.5 mm, the average venous diameter was 1.54 ± 0.7 mm. The constant blood supply to the peroneus brevis muscle by segmental branches from the fibular and tibial artery make this muscle a viable option for proximally or distally pedicled flap transfer. The location of the most proximal and distal branches to the muscle and conclusively the pivot points for flap transfer could be determined. Furthermore, a constant proximal axial vascular pedicle to the muscle may enlarge the clinical applications. Perfusion studies should be conducted to confirm these findings. © 2014 Wiley Periodicals, Inc. Microsurgery 35:39–44, 2015.     

Superficial surgical landmarks for identifying the posterior interosseous nerve

OBJECT: There is a paucity of information in the neurosurgical literature regarding the surgical anatomy surrounding the posterior interosseous nerve (PIN). The goal of the current study was to provide easily recognizable superficial bone landmarks for identification of the PIN. METHODS: Thirty-four cadaveric upper extremities obtained from adults were subjected to dissection of the PINs, and measurements were made between this nerve and surrounding superficial bone landmarks. In all specimens the main radial trunk was found to branch into its superficial branch and PIN at the level of the lateral epicondyle of the humerus. Proximally, the PIN was best identified following dissection between the brachioradialis and extensor carpi radialis longus and brevis muscles. At its exit site from the supinator muscle, the PIN was best identified after retraction between the extensor carpi radialis longus and brevis and extensor digitorum communis muscles. This site was a mean distance of 6 cm distal to the lateral epicondyle of the humerus. No compression of the PIN by the tendon of origin of the extensor carpi radialis brevis muscle was seen. One specimen was found to have a proximally split PIN that provided a previously undefined articular branch to the elbow joint. The mean diameter of the PIN proximal to the supinator muscle was 4.5 mm. The leash of Henry crossed the PIN in all but one specimen and was found at a mean distance of 5 cm inferior to the lateral epicondyle. The PIN exited the distal edge of the supinator muscle at a mean distance of 12 cm distal to the lateral epicondyle of the humerus. Here the mean diameter of the PIN was 4 mm. The exit site from the distal edge of the supinator was found to be at a mean distance of 18 cm proximal to the styloid process of the ulna. This exit site for the PIN was best identified following dissection between the extensor carpi radialis longus and brevis and extensor digitorum communis muscles. The distal articular branch of the PIN was found to have a mean length of 13 cm and the proximal portion of this terminal segment was located at a mean distance of 7.5 cm proximal to the Lister tubercle. CONCLUSIONS: The addition of more anatomical landmarks can help the neurosurgeon to be more precise in identifying the PIN and in avoiding complications during surgery in this region.     

腓肠神经-小隐静脉逆行岛状肌皮瓣的局部解剖与临床应用

目的：介绍腓肠神经-小隐静脉逆行岛状肌皮瓣的局部血管解剖研究与临床应用经验。方法解剖3个成人小腿灌注标本,观察腓肠神经-小隐静脉血管轴与腓肠肌内外侧头肌支和肌皮穿支之间的吻合关系,根据观察结果设计以腓动脉肌间隔穿支供血的逆行岛状腓肠肌皮瓣修复4例足踝部创面,皮瓣面积10～16 cm ×6～9 cm。结果在腓肠神经穿出深筋膜前,腓肠神经-小隐静脉血管轴与两侧的腓肠肌肌支间各有2～4个吻合。在穿出深筋膜后,与两侧的腓肠肌肌皮穿支间各有2～3个吻合。在腓肠肌腱腹交界（约为小腿中点）的近侧2～4 cm 内,有1～3支肌皮穿支血管与腓肠神经血管轴相交通。据此设计的肌皮瓣完全成活。结论腓肠神经-小隐静脉逆行岛状肌皮瓣血供可靠、转移方便,较传统的腓肠神经营养血管皮瓣可切取面积更大,是修复足踝部组织缺损的好方法。     

Quantitative histochemical evaluation of skeletal muscle ischemia and reperfusion injury

Acute arterial obstruction to the extremities is associated with significant morbidity and mortality. The evaluation of accompanying skeletal muscle injury has thus far been indirect and imprecise. Triphenyltetrazolium chloride (TTC) is an oxidation-reduction indicator which allows for the histochemical quantitation of skeletal muscle injury. In 21 anesthetized nonheparinized adult mongrel dogs, the isolated in vivo gracilis muscle underwent 4, 6, or 8 hr of ischemia with and without reperfusion. The muscles were excised and cut into 1-cm segments, representative muscle biopsies for electron microscopy were taken, each segment was stained in 1% TTC, and the total area of staining was measured with computerized planimetry. All control muscles stained completely with a dark red color. After 4, 6, or 8 hr of ischemia, quantitative measurements of muscle staining indicative of normal tissue were present in 98 +/- 1%, 59 +/- 5%, and 23 +/- 9% of the total muscle areas, respectively. Six hours of ischemia followed by reperfusion was associated with only 36 +/- 9% of the muscle being stained. Segmental TTC staining demonstrated that reperfusion was associated with greater injury, and less TTC staining, in the proximal portion of the gracilis muscle at the site of entry of the major arterial pedicle. The distal muscle did not demonstrate increased damage with reperfusion. It is hypothesized that protection of the distal muscle from reperfusion injury may be due to an absence of reflow farther away from the artery.