Nerves of the Upper Limb Flashcards
what innervation does the brachial plexus supply
somatomotor and somatosensory innervation to the upper extremity
what does the brachial plexus arise from
the cervical enlargement of the spinal cord
what section of the spinal cord gives rise to the brachial plexus
ventral (anterior) rami of cervical spinal nerve roots C5-T1
where do spinal nerve roots supplying the brachial plexus emerge from and what do they pass through
intervertebral formaina of cervical vertebrae and pass between the anterior and middle scalene muscles (interscalene space) of the neck
where does the brachial plexus emerge
posterolateral to the sternoclediomastoid muscle in the lateral neck region in the posterior triangle through the interscalene space at the level of the cricoid cartilage of the larynx
the brachial plexus maintains an anatomical relationship with subclavian artery and vein as it travels where
posterior to the omohyoid muscle and the clavicle on its way to the axilla
what is an interscalene block used for
anesthesia of the brachial plexus to temporarily block sensation and motor function to the upper limb
what is a common complication of interscalene blocks
accidental partial anesthesia of the diaphragm and temporary respiratory depression due to the proximity of phrenic nerve (C3-C5) to the anterior scalene muscle and compartmentalization of fascia within the neck
what portion of the spinal cord does the phrenic nerve and the brachial plexus overalp
C5
when doing an interscalene block what anatomical relationships must you have knowledge of
posterior triangle of the neck
what does the brachial plexus pass as it enters the axillary region
travels posterior to the pectoralis minor where it forms a relationship with the axillary artery such that the artery runs in the middle of the plexus and is surrounded by the cords and terminal branches
what is the axillary vein’s relationship with the brachial plexus
the axillary vein and its tributaries entangle themselves with the branches of the brachial plexus
as the brachial plexus runs into the axilla and along the axillary artery and vein what is it surrounded in
surrounded in a neurovascular bundle by the axillary sheath
what does the axillary sheath contain
axillary vein, axillary artery, brachial plexus
what are the features of the brachial plexus
lateral cord, medial cord, and posterior cord
what is a dermatome
area of cutaneous sensory innervation supplied by a single spinal nerve
what dermatomes does C4 supply
supraclavicular and upper shoulder region
what dermatomes does C5 supply
upper lateral arm and shoulder
what dermatomes does C6 supply
posteriolateral arm and lateral forearm
what dermatomes does C7 supply
middle of forearm and hand
what dermatomes does C8 supply
posteriomedial forearm and medial hand
what dermatomes does T1 supply
medial arm
what dermatomes does T2-T5 supply
axillary region
what spinal nerves do T2-T5 respond to
intercostal nerves
what spinal nerve does T1 respond to
medial antebrachial cutaneous nerve and medial brachial cutaneous nerve
what nerve does C8 respond to
ulnar nerve
what nerve does C7 respond to
median nerve
what nerves does C6 respond to
median nerve, radial nerve, and musculocutaneous nerve
what nerve does C5 respond to
superior lateral brachial cutaneous nerve (axillary nerve)
what nerve does C4 respond to
superior lateral brachial cutaneous nerve (axillary nerve) and supraclavicular nerves
how many spinal nerves supply an individual named muscle in the limbs
more than one
what is a myotome
a group of muscles that receive motor innervation from a single spinal nerve
what are the divisions of the trunks of the brachial plexus
anterior and posterior division
what do the divisions of the trunks of the brachial plexus contribute to
branches that correspond to anterior parts of the limb or posterior parts of the limb
what muscles are in the anterior compartment of the upper extremity
biceps and brachialis
what nerve innervates the muscles in the anterior compartment of the upper extremity
musculocutaneous nerve