Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
ORIGIN OF THE LONG HEAD OF TRICEPS Abduelmenem Alashkhama,b, Abdulrahman Alraddadia,c, Roger Soamesa a Centre for Human Anatomy and Identification, University of Dundee, Dundee, UK b Human Anatomy Department, Faculty of Medicine, University of Zawia, Zawia, Libya c Human Anatomy Department, Faculty of Medicine, King Saud Bin Abdulaziz University for Health Sciences , Riyadh, Saudi Arabia. ABSTRACT Anatomical anomalies of triceps are not common. During the course of a cadaveric dissection in CAHID a rare bilateral variation of the attachment of the long head of triceps was found in a 62 year old female cadaver. The long head of triceps was attached to the infraglenoid tubercle and the posteroinferior aspect of the glenohumeral joint capsule, as well as by a fibrous extension between 3 to 4 cm long to the superior part of the lateral border of the scapula. INTRODUCTION Triceps is a large, strong fusiform muscle in the posterior compartment of the arm (Smith et al., 1983; Palastanga et al., 2006). It has three heads, the long head arising from the scapula and the medial and lateral heads from the posterior aspect of the humerus (Rogers, 1992; Lumley et al., 1995). The medial head is the deepest taking origin from the lower half of the posterior aspect of the humerus and the intermuscular septa inferior and medial to the spiral groove AXIS Vol. 4, Issue 2 (Spring 2013) (Abrahams et al., 2011; Sinnatamby, 2006). The lateral head is superficial and lateral; having a linear attachment from the superior lip of the spiral groove and the posterior surface of the upper 1/3rd of the humerus between the attachment of deltoid and teres minor as far superior as the surgical neck of the humerus: it descends bridging over the spiral groove forming its roof (Snell, 1995; Moore et al., 2010). The long head is superficial and medial, coming from the infraglenoid tubercle and glenoid labrum. It passes downwards interposed between teres minor (posterior) and teres major (anterior), running superficial to the medial head of triceps. It forms the medial border of both the quadrilateral and lower triangular spaces. The long and lateral heads descend to join the medial head, with the lateral head covering the radial nerve and profunda brachii vessels in the spiral groove (Monkhouse, 2001; Drake et al., 2005). Fusion of the three heads above the elbow gives rise to a broad laminated tendon which is inserts into the summit of the olecranon process of the ulna. The tendon is separated by a bursa from the posterior region of the 1 elbow joint (Faiz and Moffat, 2006; Palastanga et al, 2006). The three heads of triceps are supplied separately by branches from the radial nerve (Hall-Craggs, 1990; Ellis, 2006). Triceps extends the forearm at the elbow joint. In addition, as the long head crosses the shoulder joint it helps in adduction and extension of the arm, supports the head of the humerus when the upper limb is abducted counteracting inferior translation of the humeral head (Sinnatamby, 2006; Palastanga et al., 2006; Moore et al., 2010). Triceps anomalies have seldom been reported in the literature. In an assessment of twenty fresh cadaveric shoulders (10 males, 10 females, mean age 65.8 years) Handling et al (2010) reported that the long head of triceps originates from the infraglenoid tubercle, posterior aspect of the upper part of the lateral border of the scapula with a persistent attachment to the inferior aspect of the capsule of the shoulder joint: the mean width and thickness of the lateral and medial aspects of the tendon of the long head of triceps were 26.9 mm, 4.7 mm and 2.9 mm respectively. In an evaluation of 15 fresh cadaveric shoulders Eiserloh et al (2000) reported that the long head of triceps brachii originated from the infraglenoid tubercle with a contribution from the posteroinferior aspect of the fibrous capsule of the shoulder joint. The mean width and thickness of the long head origin were 29.5 mm (range, 26 - 34 mm) and 5.7 mm (range 4 - 7 mm) respectively. The authors noted that in all specimens a fibrous extension, with an average length of 3.7 mm, was consistently present from the bony attachment of the long head of triceps to the posteroinferior aspect of the capsule where it was stretched in AXIS Vol. 4, Issue 2 (Spring 2013) abduction and external rotation as well as in flexion and internal rotation. It was considered that the cardinal functions of the fibrous extension is to (1) counteract the inferior translation of the humeral head during abduction, especially when it exceeds 90 degrees, and (2) tense the capsule substantially when the arm is rotated. Tubbs et al (2006) have reported that the medial head of triceps is attached to the posterior region of the surgical neck of the humerus having a length of 6.5 cm and a width of 0.5 cm. Soubhagya et al (2007) also reported that the medial head of triceps had a further bony origin, suggesting that triceps has four heads with the fourth head attaching to the medial aspect of the humerus inferior to the insertion of teres major and latissimus dorsi. The length and width of the fourth head were 6 cm and 1.6 cm respectively. Earlier Fabrizio and Clemente (1997) reported a unilateral fourth head of triceps arising from the posteromedial aspect of the humerus just superior to the insertion of teres major parallel to the lateral head of triceps. The tendon passed inferiorly on the medial side of the humerus deep to the medial head in the lower third of the arm, as well as having a direct relation to the profunda brachii artery and radial nerve as they pass to the radial groove: it attached to the medial aspect of the olecranon process of the ulna. 2 CASE REPORT During dissection of the shoulder of a 62 year old female, the long head of triceps was observed to have an extended attachment. In addition to its origin from the infraglenoid tubercle there was some contribution from the posteroinferior aspect of the glenohumeral capsule, a fibrous slip to the superior part of the lateral border of the scapula on both sides (Fig. A, B). The mean width, medial and lateral thickness of the extension on the right side were 25 mm, 3.8 mm, 5 mm and on the left 26 mm, 3.3 mm, 5 mm respectively. The long head passed distally to blend with the lateral and medial heads before inserting into the olecranon process of the ulna via a broad tendon. There was no anatomical variation in relation to teres minor and major, the triangular interval, or the quadrangular and triangular spaces and their contents. Knowledge of the anatomical variation of the long head of triceps is important because it has a contribution to the posteroinferior aspect of the fibrous capsule of the shoulder joint, and may be damaged during open or arthroscopic surgery of the shoulder joint. As a consequence there could be a decrease in the posteroinferior support of the fibrous capsule to the head of humerus which could potentially lead to dislocation of the shoulder joint. More studies are therefore needed to investigate the long head of triceps and its potential contribution to the biomechanics of the shoulder joint. Figures A (right scapula) and B (left scapula) illustrate the origin of the long head of triceps. AXIS Vol. 4, Issue 2 (Spring 2013) 3 AXIS Vol. 4, Issue 2 (Spring 2013) 4 References: Abrahams P, Craven J, Lumley J (2011) Illustrated Clinical Anatomy London, Arnold. Drake RL, Vogl AW, Mitchell AWM (2005) Gray`s Anatomy for Students Philadelphia, Churchill Livingstone Elsevier Eiserloh H, Drez D, Guanche CA (2000) The long head of the triceps: A detailed analysis of its capsular origin. Journal of Shoulder and Elbow Surgery, 9:332-335. Ellis H (2006) Clinical Anatomy: a revision and applied anatomy for clinical students Oxford, Blackwell Publishing. Moore KL, Dalley AF, Agur AMR (2010) Clinical Variation in the triceps brachii muscle: A fourth muscular head. Clinical Anatomy, 10, 259-263. Faiz O, Moffat D (2006) Anatomy at A Glance Oxford, Blackwell Publishing Hall-Craggs ECB (1990) Anatomy as a Basis for Clinical Medicine London, Williams & Wilkins Handling MA, Curtis AS, Miller SL (2010) The origin of the long head of the triceps: A cadaveric study. Journal of Shoulder and Elbow Surgery, 19:69-72. Lumley JSP, Craven JL, Aitken JT (1995) Essential Anatomy and clinical applications Edinburgh, Churchill Livingstone. AXIS Vol. 4, Issue 2 (Spring 2013) Oriented Anatomy Philadelphia, Pa.; London Lippincott William and Wilkins Palastanga N, Field D, Soames R (2006) Anatomy and Human movement: structure and function Edinburgh, Butterworth Heinemann Elsevier Rogers AW Anatomy Fabrizio, PA, Clemente FR (1997), some Stanley (2001) Clinical anatomy: A core text with selfassessment Edinburgh: Churchill Livingstone. Monkhouse (1992) Textbook Edinburgh, of Churchill Livingstone. Soubhagya R, Ashwin K, Kumar MS, Latha V, Vasudha S, Merin M (2008) Four-headed biceps and triceps brachii muscles, with neurovascular variation. Anatomical Science International 83:107-111. Snell R S (1995) Clinical Anatomy for Medical Students, 5TH edition Boston Mass., London: Little, Brown Sinnatamby CS (2006) Last’s Anatomy: regional and applied Edinburgh, New York, Elsevier/ Churchill Livingstone Smith JW, Murphy TR, Blair JSG, Lowe KG (1983) Regional Anatomy 5 Illustrated Livingstone Edinburgh Churchill demonstrating a fourth head. Clinical Anatomy 19:657-660. Tubbs RS, Salter EG, Oakes WJ (2006) Triceps brachii muscles AXIS Vol. 4, Issue 2 (Spring 2013) 6