Upper Limb session 1 Flashcards
Scapular Articulates with….
It articulates with the humerus at the glenohumeral joint, and with the clavicle at the acromioclavicular joint. connects the upper limb to the trunk
the fossa of the scapular ….
It contains a largeconcave depression over most of its surface, known as thesubscapular fossa.
Glenoid fossa–a shallow cavity, located superiorly on the lateral border. It articulates with the head of the humerus to form theglenohumeral (shoulder) joint
Tubercles of the Scapular
Supraglenoid tubercle–a roughening immediately superior to the glenoid fossa. The place of attachment of the long head of the biceps brachii.
Infraglenoid tubercle–a roughening immediately inferior to the glenoid fossa. The place of attachment of the long head of the triceps brachii
Infraspinous fossa– the area below the spine of the scapula, it displays a convex shape.
Supraspinous fossa– the area above the spine of the scapula, it is much smaller than the infraspinous fossa, and is more convex in shape.
Theposterior surfaceof the scapula features
• Spine– the most prominent feature of the posterior scapula. It runs transversely across the scapula, dividing the surface into two.
• Acromion–projection of the spine that arches over the glenohumeral joint and articulates with the clavicle at the acromioclavicular joint.
• Infraspinous fossa– the area below the spine of the scapula, it displays a convex shape.
Supraspinous fossa– the area above the spine of the scapula, it is much smaller than the infraspinous fossa,
Clavicle shape and articulation
Theclavicle(collarbone) extends between the manubrium of the sternum and the acromion of the scapula.
sternal end contains alarge facet– for articulation with the manubrium of the sternum at thesternoclavicular joint
Functions of the clavicle
clavicle has three main functions: Attaches the upper limb to the trunk as part of the ‘shoulder girdle’, Protects the underlying neurovascular structures supplying the upper limb, Transmits force from the upper limb to the axial skeleton.
Muscles that attach to the clavicle
attachment for several muscles – deltoid, trapezius, subclavius, pectoralis major, sternocleidomastoid and sternohyoid
what is the acromioclavicular joint
The acromial end houses a small facet for articulation with the acromion of the scapula at theacromioclavicular joint
what type of joint is the shoulder joint
The shoulder joint (glenohumeral joint) is a ball and socket joint between thescapula and thehumerus
It is the major joint connecting the upper limb to the trunk.
what articulates at the shoulder?
articulation of theheadof the humerus with theglenoid cavity(or fossa)of the scapula.
what features are seen in the shoulder joint
- Like most synovial joints, the articulating surfaces are covered withhyaline cartilage.
- The head of the humerus is much larger than the glenoid fossa, giving the joint a wide range of movement at the cost of inherent instability.
- To reduce the disproportion in surfaces, the glenoid fossa is deepened by a fibrocartilage rim, called theglenoid labrum.
- Thejoint capsuleis a fibrous sheath which encloses the structures of the joint
- It extends from theanatomical neckof the humerus to the border or ‘rim’ of the glenoid fossa.
- Thesynovial membranelines the inner surface of the joint capsule, and produces synovial fluid to reduce friction between the articular surfaces.
Factors that contribute to stability of the shoulder joint
• Rotator cuff muscles– surround the shoulder joint,attaching to the tuberosities of the humerus, whilst also fusing with the joint capsule. The resting tone of these muscles act to compress the humeral head into the glenoid cavity.
• Glenoid labrum–a fibrocartilaginous ridge surrounding the glenoid cavity. It deepens the cavity and creates a seal with the head of humerus, reducing the risk of dislocation.
• Ligaments–act to reinforce the joint capsule, and form the coraco-acromial arch.
Biceps tendon–it acts as a minor humeral head depressor, thereby contributing to stabilit
Neurovasculature supply to the shoulder joint?
The shoulder joint is supplied by theanteriorandposterior circumflex humeral arteries, which are both branches of the axillary artery. Branches of thesuprascapular artery, a branch of the thyrocervical trunk, also contribute.
Innervation is provided by theaxillary,suprascapularandlateral pectoralnerves
Name the two superficial extrinsic muscles
There are two superficial extrinsic muscles – the trapezius and latissimus dorsi
What is the trapezius
The trapezius is a broad, flat and triangular muscle. The muscles on each side form a trapezoid shape. It is the most superficial of all the back muscles.
Origin of the trapezius
. Originates from the skull,nuchalligament and thespinous processes of C7-T12. The fibres attach to the clavicle, acromion and the scapula spine
Action of the trapezius
The upper fibres of the trapezius elevate the scapula and rotates it during abduction of the arm. The middle fibres retract the scapula and the lower fibres pull the scapula inferiorly.
What is the latissimus dorsi
The latissimus dorsi originates from the lower part of the back, where it covers a wide area.
Origin of the latissimus dorsi
Has a broad origin – arising from the spinous processes of T7-T12, iliac crest, thoracolumbar fascia and the inferior three ribs. The fibres converge into a tendon that attaches to the intertubercular sulcus of the humerus.
Action of the latissimus dorsi
Extends, adducts and medially rotates the upper limb.
What are Rhomboids
There are two rhomboid muscles – major and minor. The rhomboid minor is situated superiorly to the major.
Where does the Rhomboid Major Originate
Rhomboid Major
Originates from the spinous processes of T2-T5 vertebrae.
Where does the Rhomboid Major articulate
Attaches to the medial border of the scapula, between the scapula spine and inferior angle.
Rhomboid Major action
Retracts and rotates the scapula.
Where does the Rhomboid Minor Originates
Rhomboid Minor
Originates from the spinous processes of C7-T1 vertebrae
where does the Rhomboid Minor attach
Attaches to the medial border of the scapula, at the level of the spine of scapula.
Rhomboid Minor action
Retracts and rotates the scapula.
lis the four rotator cuff muscles =
four rotator cuff muscles (supraspinatus, infraspinatus, subscapularis and teres minor)
What is the delta muscle
The deltoid muscle is shaped like the Greek letter delta – Δ. It can be divided into an anterior, middle and posterior part.
Where does the delta muscle originate
Originate from the lateral third of the clavicle, the acromion and the spine of the scapula. It attaches to the deltoid tuberosity on the lateral aspect of thehumerus
Delta muscle actions (all 3 sections )
Anterior fibres – flexion and medial rotation. Posterior fibres – extension and lateral rotation. Middle fibres – the major abductor of the arm (takes over from the supraspinatus, which abducts the first 15 degrees).
What is the teres major
The teres major forms the inferior border of the quadrangular space – the ‘gap’ that theaxillary nerveand posterior circumflex humeral artery pass through to reach the posterior scapula region
Where does there teres major originate
Originates from the posterior surface of the inferior angle of the scapula. It attaches to the medial lip of the intertubercular groove of the humerus.
Action of the teres major
Adducts at the shoulder and medially rotates the arm.
Role of the rotator cuff muscles
The rotator cuff muscles are a group of four muscles that originate from the scapula and attach to the humeral head. Collectively, the resting tone of these muscles acts to ‘pull’the humeral head into the glenoid fossa. This givestheglenohumeral joint a lot of additional stability.
In addition to their collective function, the rotator cuff muscles also have their own individual actions.
Supraspinatus- origin and action
Originates from the supraspinous fossa of the scapula, attaches to the greater tubercle of the humerus. Abducts the arm 0-15o, and assists deltoid for 15-90o
Infraspinatus - origin and action
Originates from the infraspinous fossa of the scapula, attaches to the greater tubercle of the humerus. Laterally rotates the arm.
Subscapularis - origin ad naction
Originates from the subscapular fossa, on the costal surface of the scapula. It attaches to the lesser tubercle of the humerus. Medially rotates the arm.
Teres Minor - origin and actions
Originates from the posterior surface of the scapula, adjacent to its lateral border. It attaches to the greater tubercle of the humerus. Laterally rotates the arm.
