Written Examination Part III. (30 pts) - Short Answer (October 6, 2006)

* Indicate your understanding (characteristics, importance, function, relationships, boundries and/or contents) of the following.

Elbow Anastamosis

Arteries involved superior to the elbow:

Brachial Artery: Superior Ulna Collateral posteriomedially at or about the middle arm and then courses with the ulnar nerve. Inferior Ulnar Collateral courses anteriomedially just above the medial epicondyle.

Brachii Profunda: Middle collateral artery posteriolaterally Radial collateral artery anteriolaterally.

Inferior to elbow:

Radial artery: Smaller terminal medial branch of the brachial artery Branches into radial recurrent anteriolaterally following the course of the radial nerve. At about the level of the radial head. Deep in the cubital fossa, medial to the bicep tendon, on the anterior surface of the brachialis muscle.

Ulnar artery: Larger terminal medial branch of the brachial artery branches into common interosseous and then the interosseous recurrent which courses posteriolaterally through the window created by the oblique cord and the interosseous membrane.

The ulnar artery also branches as the ulnar recurrent which splits as the anteriorly ulnar recurrent artery anterior to the medial epicondyle posterior ulnar recurrent artery posterior to the medial epicondyle. Forms the circumtrochlear anastomosis.

Suboccipital Triangle

Medially: Rectus Capitis Posterior Minor: between the superior and inferior Nuchal lines to C1. Medially: Rectus Capitis Posterior Major: between the superior and inferior Nuchal lines to spine of C2. Laterally-Superior: Obliquus Capitis Superior: between the superior and inferior Nuchal lines to transverse process of C1. Laterally-Inferior: Obliquus Captius Inferior: Transverse process of atlas to Spine C2 Floor: Atlas Roof: Semispinalis Capitus Contents: Vertebral Artery (running medially along the posterior arch), Suboccipital Nerve – Dorsal Ramus of C1 (Supplies all 4 muscles) External Venous Plexus Greater Occipital Nerve – Dorsal Ramus of C2 - crosses posterior to the triangle as it courses superiorly over the to the back of the head. Function: Rotating and Extending the Head.

Posterior Cord of the Brachial Plexus

Posterior cord is derived from the posterior divisions from the superior, middle, and inferior trunks of the brachial plexus Consists of fibers arising from C5 to T1. Provides innervation for the extensor compartment of the Arm and Forearm as well as cutaneous innervation of the skin on the dorsum of the hand, forearm, arm, and shoulder. The posterior cord terminates as the Axillary N. C5-T1 and the Radial N. C-5-C6. Located posterior to the axillary artery. Lesions - loss of sensation to the posterior aspect of arm,forearm,and hand. Motor deficits in extensor regions of arm and forearm.

Nerves of the Palm of the Hand

Median N. chief nerve of sensation in the palmar surface of the hand. With exception to the muscle of the thenar emminance. Ulnar N. chief motor nerve of the hand (intrinsic muscles) and sensory to only the ulnar 1 and ½ fingers.

Median N. enters hand on radial side of the Palmaris longus tendon deep to the flexor retinaculum. Breaks into a recurrent branch (to the thenar emminance) the remaining branch terminating in the common palmar digital nerve, to the proper palmer digital n. Branches are embedded in loose connective tissue on the deep surface of the palmar aponeurosis.

Communication branch between the Ulnar and Median Nerve.

Ulnar N. enters the hand on the lateral side pisiform bone with the ulnar artery. Superficial to the flexor retinaculum but deep to the superficial lamina of the flexor retinaculum in the canal of Guyon. At the pisiform splits into the superficial and a deep branch. Deep branch of the ulnar N. will branch into Articular Nerves. Superficial Ulnar N. which branches into a communicating branch and common palmar digital and then palmar digital. They are cutaneous with the exception to the motor branch that goes to the Palmaris brevis. Deep branch provides innervation to the hypothenar muscles, interossei, ulnar two lumbricals, adductor pollicis, deep head of the the flexor pollicis brevis, and rarely the opens pollicis.

Distal branches will travel in the palm of the hand head along the palmar surface of the hand as it travels distally, to supply the nail beds on the dorsum of the hand.

Flexor Digitorum Profundus

Located in the deep portion of the anterior of flexor region of the anterior compartment. Courses deep in the carpal tunnel.

Innervation: Lateral two tendons Anterior interosseous N. (branch of the median) C-7 Medial two digits innervated by the Ulnar nerve. C-8 T1

Origin: anterior and medial surfaces of the ulna and adjacent interosseous membrane.

Inserts: Distal Phalanx of 4 lateral digits

Function: Weak Flexor of the wrist, MP joints, and IP joints. Only works as a flexor of the wrist if distal digits are extended.

Top of page

Comments and Suggestions

 
Top of page

-- ThomasPerrault - 21 Nov 2006
Topic revision: r1 - 21 Nov 2006, UnknownUser
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding Structural Basis of Medical Practice? Send feedback