MSK exam 1 Flashcards
Delto Pectoral triangle
AKA clavipectoral triangle
- Pectoralis Major
- Deltoid Major
- Clavicle
Contents: Cephalic Vein and Deltopectoral Fascia
-Subclavian Vein and Subclavian artery are Deep to this triangle
Axillary Nerve
Innervates: Deltoid muscle and Teres minor muscle.
-The axillary nerve courses around the surgical neck of the humerus Injured during a fracture or during an inferior dislocation of the shoulder joint.
Quadrangular Space
superior, lateral, medial, inferior borders, contents
Superior border- Inferior border of the teres minor muscle
Lateral border- surgical neck of the humerus
Medial border- lateral border of the long headof the triceps brachii muscle
Inferior border - superior border of the teres
major muscle
Contents: Axillary nerve and posterior humeral Circumflex
Thoracodorsal Nerve
- extend, adduct, and medially rotate the arm
- Latissimus Dorsus
Cubital Fossa
Borders:
- Medial epicondyle, Lateral Epicondyle
- Pronator Teres, Brachialis
Contents: lateral —–> medial
- Radial nerve
- Tendon of the Biceps Brachii
- Brachial Artery —–> bifurcates into Radial artery and Ulnar artery
- Median Nerve
- *Aponeurosis goes medially from tendon of the biceps brachii covers everything EXCEPT the radial nerve
- roof: skin, fascia, bicipital aponeurosis
- floor: supinator and brachilis
Collateral and recurrent arteries of the arm
Axillary artery becomes brachial artery at the teres major
Acronym is medial to lateral
• Mr. Deep, Middle collateral artery, Radial Collateral (Branches off profunda brachii or deep)
• Superior ulnar collateral, Inferior ulnar collateral, Middle collateral, Radial Collateral
• Posterior ulnar recurrent (off ulnar artery), Anterior ulnar recurrent (off ulnar artery), Interosseous recurrent (off radial) , Radial Recurrent (off radial)
SIMR PAIR
-SUC goes posterior to medial epicondyle
-IUC goes anterior to the medial epicondyle (infant)
Triceps
-Long head of the triceps brachii muscle – attaches to the infraglenoid tubercle of the scapula
-Lateral head of the triceps brachii muscle – attaches to the posterior surface of the humerus
lateral to the radial groove
-Medial head of the triceps brachii muscle –
attaches to the posterior surface of the humerus medial to the radial groove
Biceps
Origin))
-Short head: Coracoid process of the scapula.
-Long head: Supraglenoid Tubercle
Insertion))
Radial tuberosity and bicipital aponeurosis into deep fascia
Artery)) Brachial artery
Nerve)) Musculocutaneous nerve (C5–C6)
Actions)) Flexes elbow and supinates forearm
Ionotropic channel linked receptor in ANS
Nicotinic acetylcholine (ACh) receptor -found at the neuromuscular junction, in postganglionic neurons of ANS, and in parts of the CNS.
-Curare and Snake toxins (competitive antagonist) block binding of Ach to its nicotinic receptor. In the case of the neuromuscular junction, this induces paralysis.
Other ion-channel linked or ionotropic receptors
- IP3 receptor (ER; Ca+2 channel)
- Ca+2 or ryanodine receptor
- AChR superfamily: serotonin, GABA, glycine receptors
NICOTINIC DO NOT USE G PROTEINS
Somatic Skeletal Muscles
Neuromuscular junction
G proteins that regulate ion channels
-In the heart, ACh from the vagus n. (parasympathetic) causes decreased rate and strength of contraction.
-In atria, this is mediated by muscarinic ACh receptors (7-pass receptors) that work through large G proteins (unlike the nicotinic ACh receptors we discussed earlier).
Activated receptor liberates beta gamma subunits, which bind to a plasma membrane K+ channel, open it, increase K+ permeability, increase K+ efflux from myocytes, hyperpolarize the myocytes, and make them harder to “fire”
MUSCARINIC= G PROTEIN REGULATION
Upper Subscapular and Lower Subscapular Nerves
Upper subscapular nerve
Lower subscapular nerve
Posterior division of the brachial plexus.
- -The upper subscapular innervates the upper portion of the subscapularis muscle.
- -The lower subscapular nerve contains two branches. One branch inserts into the lower portion of the subscapularis muscle and the other branch inserts into the teres major.
The middle subscapular nerve, known as the thoracodorsal. This nerve innervates the latissimus dorsi muscle.
M Nerves
- Medial cutaneous nerve of the arm
- Medial cutaneous nerve of the forearm (antebrachial)
Both arise from the median nerve of the Arm
Cartilage
3 types of Cartilage
- -Hyaline cartilage long bones, epiphyseal plates, articular surfaces of synovial joints
- -Fibrocartilage Discs within joints (e.g. menisci of knee)
- -Elastic cartilage highly flexible (e.g. auricle of ear, epiglottis)
Flexors of the forearm
- superficial
- deep
Superficial: pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, pronator teres
Deep: Flexor pollicis longus, flexor digitorum Profundus, pronator quadratus)
Extensors of the forearm
- Deep
- Superficial
Deep:
Anconeus, supinator, extensor indices, extensor pollicis longus, extensor pollicis brevis, abductor pollicis longus
Superficial: extensor carpi radialis longus, extensor carpi radialis brevis, extensor digitorum, extensor digit minimi, extensor carpi ulnaris
