2- Bones and the Skeleton Flashcards
How are the upper limbs attached to the axial skeleton?
Sternoclavicular joint attaches medial aspect of clavicle to the manubrium of the sternum.
What is apposition, reposition, and opposition?
Apposition- touching of 5th digit to thumb
Reposition- Release of fingers
Opposition- gripping with fingers
What are some roles/facts of the clavicle?
Joins axial skeleton to upper limbs
Sternoclavicular ligaments are so strong, bone will break before disjoining
Transmits weight
Acts as a strut
Slight sigmoid curves (concave laterally, convex medially)
What are key features of the scapula?
Acromion- lateral, articulates with clavicle to form acromioclavicular joint.
Coracoid process- Used for muscular/ligament attachments
Spine- sharp ridge, posterior, splits scapula into supraspinous and infraspinous fossa
Glenoid Cavity- Lateral, articulates with humerus
Subscapular Fossa- Anterior surface where muscles pass over.
What muscles hold the scapula in place?
Trapezius Levator Scapula Rhomboid Major/Minor Serratus Anterior Pectoralis Minor
What is protraction/retraction of the scapula?
Protraction- pushing a door open, separating the scapula
Retraction- pulling scapulae together.
What muscles make up the posterior wall of the axilla?
Subscapularis, Teres major, Latissimus Dorsi, and long head of triceps brachii
What muscles make up the anterior wall of the axilla?
Pectoral Muscles
What landmarks form the lateral and medial borders of the axilla?
Medial- Upper thoracic wall and Serratus Anterior
Lateral- Intertubercular sulcus of humerus and muscles
What is the origin and insertion of pectoralis major?
Origin- Anterior, medial clavicle, sternum, upper 6 costal cartilage, aponeurosis of external oblique (fibrous tissue, takes place of tendon in flat muscle)
Insertion- Crest of greater tubercle and lateral lip of intertubercle groove (lower fibres form U-shaped tendon)
What action does pectoralis major cause?
Protracts and depresses scapula
Adducts and medially rotates humerus
Clavicular head can flex humerus
Sternocostal head can extend humerus
What nerve(s) innervate pectoralis major?
Medial and Lateral pectoral nerves coming from brachial plexus
What is the origin and insertion of pectoralis minor?
Origin- 3-5th ribs near costochondral junction
Insertion- Medial border and superior surface of the coracoid process of the scapula
What are the actions caused by pectoralis minor?
Depresses shoulder
Scapular protraction
Raises ribs when scapula is fixed
What nerve(s) innervate pectoralis minor?
medial pectoral nerve
What nerves form the brachial plexus?
Ventral rami of C5-T1 spinal nerve roots
C4 and T2 have minor contributions
What nerve fibres form the superior trunk of the brachial plexus?
C5 and C6
What nerve fibres form the middle trunk of the brachial plexus?
C7
What nerve fibres form the inferior trunk of the brachial plexus?
C8 and T1
What divisions form the lateral cord of the brachial plexus?
Anterior divisions of the superior (C5/6) and middle (C7) trunks
What divisions form the posterior cord of the brachial plexus?
Posterior divisions of the superior (C5/6), middle (C7), and inferior (C8/T1) trunks
What divisions form the medial cord of the brachial plexus?
Anterior division of the inferior (C8/T1) trunk
What cords and roots form the musculocutaneous terminal root of the brachial plexus?
Lateral cord of anterior divisions of the superior (C5/6) and middle (C7) trunks
What nerve roots form the musculocutaneous terminal root of the brachial plexus?
C5/6/7