BM 1041:03 Lecture Notes - Lecture 22: Flexor Digitorum Profundus Muscle, Flexor Carpi Ulnaris Muscle, Deep Artery Of Arm
23 May 2018
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Spinal nerves
Screen clipping taken: 30/04/2018 7:15 PM
Spinal nerves present along length of spinal cord
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Where the CNS and PNS connect
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Spinal nerves take motor information to body systems, deliver info about sensations to CNS
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C1 - C8
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T1 - T12
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L1 - L5
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S1 - S5
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C0
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31 spinal nerves, named after vertebral regions from which they emerge, numbered according to location of intervertebral canal
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Dorsal and ventral roots merge to form spinal nerves which carry mixed sensory and motor info to the relevant body area
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Spinal nerves branch into a larger central (anterior) rami (rami = branch) and a smaller dorsal (posterior) rami
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Screen clipping taken: 30/04/2018 7:28 PM
Somatic: rami
L1 - Neurovascular structures of the upper limb
Monday, 30 April 2018
7:08 PM
wk 10 Page 1
Brachial plexus innervates upper limb
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Major nerves that innervate the arm, forearm and hand originate from brachial plexus in the axilla
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Somatic plexus formed by anterior rami of C5 to C8 and most of anterior ramus of T1
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Origin: neck
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Continues through axillary inlet into axilla, passes laterally and inferiorly over rib I
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Insertion: axilla
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All major nerves that innervate upper limb originate from brachial plexus, mostly from the cords
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Proximal parts are posterior to the subclavian artery in the neck
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More distal regions surround axillary artery
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Innervation
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Describe the anatomy of the brachial plexus from its origin in the neck to its terminal branches.
Parts (medial to lateral)
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roots
Anterior rami of C5-C8 and most of T1
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trunks
Superior trunk = union of C5 and C6 roots
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Middle trunk = continuation of C7 root
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Inferior trunk = union of C8 and T1 roots
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3 trunks which originate from roots, passing laterally over rib I and enter the axilla
divisions
3 anterior divisions form parts of brachial plexus that ultimately give rise to peripheral nerves associated with
anterior compartments of arm and forearm
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3 posterior divisions - combine to form parts of brachial plexus that give rise to nerves associated with the
posterior compartments
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3 trunks divide into anterior and posterior division
NB - NO PERIPHERAL NERVES originate directly from the division so of the brachial plexus
cords
Lateral cord - union of the anterior divisions of the upper and middle trunks, contribution from C5 to C7,
positioned lateral to second part of axillary artery
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Medial cord - continuation of the anterior division of the inferior trunk, contains contributions from C8 to T1,
medial to second part of axillary artery
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Posterior cord - union of all 3 posterior divisions, contains contributions from all roots of brachial plexus C5-T1,
posterior to second part of axillary artery
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3 cords of brachial plexus originate from the divisions, related to the second part of the axillary artery
Nerves associated with anterior compartments of upper limb -> arise form medial and lateral cords
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Nerves associated with posterior compartments -> posterior cord
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Most major peripheral nerves of upper limb originate from the cords of the brachial plexus
Screen clipping taken: 30/04/2018 8:19 PM
Clinical testing of lower cervical and T1 nerves is done by examining dermatomes, myotomes and tendon reflexes in the upper limb
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Clinical signs of problems related to lower cervical nerves e.g. pains, pins and needles, paresthesia, muscle twitching - appear in the upper
limb
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Describe the origin, course and function of the axillary, radial, musculocutaneous, median and ulnar
nerves in the upper limb.
Main nerves
wk 10 Page 2
Main nerves
Axillary nerve
Musculo-
cutaneous nerve
Large terminal branch of lateral cord
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Origin: axilla
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Passes laterally through coracobrachialis muscle and pass between the biceps brachii
and brachialis muscles in the arm
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Innervates all 3 flexor muscles in the anterior compartment of the arm
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Terminates as lateral cutaneous nerve of forearm
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Median nerve
Formed by union of lateral and medial roots originating from the lateral and medial
cords of the brachial plexus
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Passes into arm anterior to brachial artery, through arm into forearm, then branches
innervate most of the muscles in the anterior compartment of forearm (except for
flexor carpi ulnaris muscles and medial half of flexor digitorum profundus)
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3 thenar muscles associated with the thumb
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2 lateral lumbrical muscles associated with movement of the index and middle
fingers
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Skin over the palmar surface of the lateral three and one-half digits and over
lateral side of palm and middle of wrist
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Continues into hand innervating
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Radial nerve
Largest terminal branch of posterior cord
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Passes out of axilla and into posterior compartment of arm, passing through triangular
interval between inferior border of teres major, long head triceps brachii, and shaft of
humerus
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Accompanied through the triangular interval by the profunda brachii artery, which
originates from the brachial artery in the anterior compartment of arm
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all muscles in the posterior compartments of the arm and forearm, and skin on
posterior aspect of the arm and forearm, lower lateral surface of the arm, dorsal
lateral surface of the hand
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Innervate
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Ulnar nerve
Large terminal branch of medial cord
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Near its origin, often communicating branch from lateral root of median nerve
originating from lateral cord and carrying fibres from C7
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Passes through arm and forearm into the hand where it innervates of the hand
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When passing through the forearm, branches of ulnar innervate the flexor carpi ulnaris
muscle and medial half of the flexor digitorum profundus muscle
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Ulnar nerve innervates skin over palmar surface of the little finger, medial half of ring
finger, associated palm and wrist, and skin over dorsal surface of medial part of the
hand
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Screen clipping taken: 30/04/2018 11:12 PM
wk 10 Page 3
Document Summary
L1 - neurovascular structures of the upper limb. Spinal nerves present along length of spinal cord. Spinal nerves take motor information to body systems, deliver info about sensations to cns. 31 spinal nerves, named after vertebral regions from which they emerge, numbered according to location of intervertebral canal. Dorsal and ventral roots merge to form spinal nerves which carry mixed sensory and motor info to the relevant body area. Spinal nerves branch into a larger central (anterior) rami (rami = branch) and a smaller dorsal (posterior) rami. Screen clipping taken: 30/04/2018 7:28 pm wk 10 page 1. Describe the anatomy of the brachial plexus from its origin in the neck to its terminal branches. Major nerves that innervate the arm, forearm and hand originate from brachial plexus in the axilla. Somatic plexus formed by anterior rami of c5 to c8 and most of anterior ramus of t1. Continues through axillary inlet into axilla, passes laterally and inferiorly over rib i.
