A2 Exam 1

Frontal bone

Maxilla (left) bone

Mandible bone

Temporal Bone (right)

Sphenoid bone

Occipital Bone

Vomer bone

Ethmoid bone

Zygomatic bone

Parietal bone (right)

Nasal bone (left)

Foramen Magnum:

• Part of occipital bone

• Opening for continuity of brain stem and spinal cord

fibrous, synarthrosis joints

Hyoid bone

Temporomandibular joint (TMJ)

• Bilateral modified synovial hinge joint

• Mandibular condyle articulates with temporal bone through articular disc of TMJ

• Depression / elevation, protrusion / retrusion, and lateral deviation

Movements?

• Superior joint cavity: translation

• Inferior joint cavity: rotation

Mandibular condyle / head of mandible

• Forms the floor of the inferior TMJ cavity.

• Articulates with the temporal bone’s Mandibular fossa.

  
  

TMJ articular disc

• Sits between the temporal bone’s Mandibular fossa and the Mandibular condyle, separating the TMJ into superior and inferior cavities

Ramus of mandible

Body of Mandible

Coranoid process of mandible

Angle of mandible

Neck of mandible

1. TMJ

2. Zygomatic Arch (temporal + zygomatic bones ; landmark for finding TMJ)

3. Ramus of Mandible

4. Inferior border of mandible

5. Hypoid bone

Lateral TMJ Ligament

• Reinforces the lateral capsule and resists excessive posterior displacement of the Mandibular condyle

• Connects temporal bone to neck of mandible

Stylomandibular Ligament

• Limits excessive protrusion (little contribution to TMJ stability

• Connects Styloid process of the temporal to angle of mandible

Sphenomandibular Ligament

• Primary passive support ; acts like ropes guiding Mandibular movement

• Connects spine of sphenoid to lingula of mandible

Explain TMJ disc pathology reduction and without reduction

• Click on opening + click on closing + full ROM (disc is recaptured) = anterior displacement with reduction

• Disc stays anterior + difficulty opening = with out reduction

what vertebrae are considered upper and lower cervical spine and what are the functional joints

• Upper cervical spine: C0 (occipital condyles) -C2

• C0-C1 (AO joint) and C1-C2 (AA joint)

• Lower cervical spine: C2-C3 → C6-C7 (first intervertebral disc is at C2-C3)

Atlanto-occipital (AO) Joint

• Occipital condyles articulating with superior facets of C1 (Atlas)

• Synovial condyloid

• Flexion / Extension. Nodding your head “yes”

Atlantoaxial (AA) Joint

• 50% of cervical rotation (shaking “no”) is at AA joint

1. Median AA joint

• anterior surface of the dens (C2) ←→ posterior surface of the anterior arch of the atlas (C1)

• Synovial pivot

2. Lateral AA Joint

• Inferior facets of C1 ←→ superior facets of C2

• Synovial plane

Tectorial membrane

• Continuation of the PLL (changes around C2)

• Resists Cervical flexion

1. Alar ligaments:

• Dens ←→ Medial occipital condyle regions

• Each primarily resists contralateral rotation and lateral flexion

2. Transverse ligament of atlas:

• Resists anterior translation of C1 on C2

• Contacts posterior surface of dens but does not attach to it

3. Cruciform / Cruciate Ligament of atlas

• Transverse ligament + sup and inf longitudinal bands (weaker than transverse)

1. Posterior AO membrane

• connects posterior arch of C1 to the occiput

• provides stability and limits excessive flexion at the AO joint

2. Ligamenta flava

• Strongest resistor of flexion

1. Anterior Longitudinal Ligament (ALL)

• Resists extension

2. Nuchal Ligament

• Resists flexion and major muscle attachment site

• The supraspinous and interspinous ligaments blend into the nuchal ligament at approximately C7

Explain coupled motion in the lower vs upper cervical spine

• In the LOWER cervical spine: rotation and lateral flexion couple to the SAME side. (Right side bending → Right rotation)

• In the UPPER cervical spine: rotation and side bending couple to the OPPOSITE sides. (Right side bending → Left rotation)

Explain Atlantodental interval (ADI)

Space between posterior C1 anterior arch and anterior dens. <3mm in adults is normal, widening raises instability concerns

1. Sternoclavicular joint

• Synovial Saddle joint (elevation / depression and protraction / retraction)

2. Coracoid process

3. Acromioclavicular joint

• Synovial Plane joint

4. Acromion

5. Glenohumeral Joint

• Synovial Ball and Socket joint (F/E, ABD/ADD, IR/ER, Horizontal ABD/ ADD)

1. Acromioclavicular joint (synovial plane)

2. Posterior angle of the acromion

3. Superior angle of scapula

4. Spine of scapula

5. Roof of spine of scapula

6. medial border of scapula

7. Lateral border of Scapula

8. Inferior angle of scapula

Explain the movements of the Pectoral Girdle (Clavicle + Scapula) in Overhead Reaching

Clavicular movements:

• Elevation

• Retraction

• Posterior Rotation

Scapular movements:

• Upward Rotation

• Posterior Tilt (superior border away from thorax)

• Internal Rotation

Explain Scapulohumeral Rhythm

120 degrees from glenohumeral (GH) elevation + 60 degrees scapulothoracic (ST) upward rotation = 180 degrees of shoulder abduction in scapular plane (30-45 deg ant to frontal plane). 2:1 ratio the whole way up.

Coracohumeral Ligament

• Extrinsic

• Resists superior humeral head translation

Intrinsic Ligaments

1. Superior Glenohumeral (GH) Ligament

• Resists ER when the arm is ADD

2. Middle GH Ligament

• Resists ER when arm is “neutral”

3. Inferior GH Ligament

• Anterior band: Resists ER when arm is ABD

• Posterior band: Resists IR when arm is ABD

• Axillary fold is between ant and post fibers (purple arrow)

1. Coracoclavicular (Conoid): Resists superior displacement of the clavicle relative to the scapula

2. Coracoclavicular (Trapezoid): Resists separation and displacement between clavicle and scapula, including superior clavicular displacement.

3. Coracoacromial: Resists superior translation of the humeral head

4. Transverse Humeral Ligament: Holds long head of biceps tendon in the intertubercular groove

1. Costoclavicular Ligament: Resists elevation of the clavicle

2. Interclavicular Ligament: Resists depression of the clavicle

3. Anterior Sternoclavicular Ligament: Resists retraction of the clavicle

4. Posterior Sternoclavicular Ligament: Resists protraction of the clavicle

Acromioclavicular Ligament: Resists excessive horizontal displacement, especially anterior / posterior movement at the AC joint

What structure is this and explain the difference between a SLAP and Bankart tear.

• This is the Glenoid Labrum

• SLAP tear is located at the superior labrum and extends anterior to posterior

• Bankart tear is located at inferior anterior labrum

1. Acromion

2. Greater tuberosity

3. Intertubercular groove (ER/IR the shoulder)

4. Lesser tuberosity (ER/IR the shoulder)

5. Coracoid process

6. Medial epicondyle

7. Olecranon fossa (flex the elbow)

8. Lateral epicondyle

9. Ulnar groove

Together form the elbow joint (Hinge Joint)

1. Humeroulnar joint: synovial hinge joint allowing for flexion and extension

2. Humeroradial joint: synovial hinge joint allowing for flexion and extension

Radial / Lateral Collateral ligament

• Resists varus stress: excessive ADDuction of the forearm relative to the arm

• intrinsic

Annular Ligament

• Holds the radial head against the radial notch of the ulna, while allowing is to spin during pronation / supination

• Helps prevent displacement of the radial head during distraction (“Nursemaid’s elbow”)

• intrinsic

Oblique Cord

• Connects the proximal ulna to radius, just below the radial tuberosity

• Becomes taut during distraction / traction (think hanging or carrying a load), helping resist the radius being pulled distally.

• Transfers distraction forces from radius → ulna to share the pulling load

Interosseus Membrane

• Forms the middle radioulnar joint (a fibrous syndesmosis)

• holds the radius and ulna together while permitting pronation / supination

• Becomes taut during compression, transferring force from the radius → ulna

• Example: during a pushup, load enters mainly through the radius and is shared with the ulna

1. Medial / Ulnar Collateral Ligament

• Resists Valgus stress: excessive ABDuction of the forearm relative to the arm

• 3 bands (anterior, posterior, oblique) anterior is the strongest

• Injury cue: baseball pitcher from repeated valgus loading

• intrinsic

2. Quadrate Ligament

• stabilizes the proximal radioulnar joint and limits excessive pronation and supination

Proximal and Distal radioulnar joints

• Both are synovial pivot joints allowing pronation and supination

1. Olecranon

2. Humeroradial joint ( flex the elbow to 90 degrees, pronate / supinate)

3. Radial head

4. Radial neck

5. Lateral shaft of radius

6. Posterior shaft of ulna

7. Head of ulna

8. Styloid process of ulna

9. Dorsal (Lister’s tubercle)

10. Styloid process of radius

1. Styloid process of radius

2. Radiocarpal joint

3. Scaphoid

4. CMC - 1 joint

5. Triquetrum

6. MCP - 1 joint

7. IP joint

8. MTP joints

9. PIP joints

10. DIP joints

Joints of the Hand

• Radiocarpal (RC) Joint:

— Between Radius and scaphoid / lunate / triquetrum

— Synovial Condyloid Joint: wrist FLX/EXT and ABD/ADD (radial/ulnar deviation)

• Carpometacarpal (CMC) Joints:

— 5 total, between carpals and metacarpals

— 1st CMC (thumb) is a Synovial Saddle joint allowing thumb FLX/EXT, ABD/ADD, OPP/ REP, and circumduction

—2-5 CMC are synovial plane joints

• Metacarpophalangeal (MCP) Joints:

— Knuckles

— 1st MCP (thumb) is a Synovial Condyloid joint BUT only FLX/EXT

— 2-5 MCP are Synovial Condyloid joints and allow FLX/EXT, ABD/ADD, and combined circumduction

• PIP, DIP, IP Joints:

— All Synovial Hinge Joints, allowing FLX/EXT

—The thumb has a IP instead of PIP or DIP

1. Wrist Ulnar/Medial Collateral Ligament (UCL/MCL):

• Resists radial deviation (ABD)

2. Wrist Radial/Lateral Collateral Ligament (RCL/LCL):

• Resists ulnar deviation (ADD)

3. Posterior/Dorsal radiocarpal ligament:

• Resists excessive wrist flexion

4. Dorsal Intercarpal Ligaments (also some on palmar side just not highlighted in picture)

5. Anterior/Palmar radiocarpal ligaments:

• Resists excessive wrist extension

6. Anterior/Palmar ulnocarpal ligaments:

• Resists excessive wrist extension

Flexor retinaculum / transverse carpal ligament: forms the roof of the carpal tunnel

Finger Collateral ligaments

• Stabilize the sides of MCP/IP joints against excessive sideways movement

• Thumb MCP LCL resists excessive thumb ABD

What is the suspected result of a FOOSH

Scaphoid or distal radius fracture

The shape of the distal radius favors:

Flexion > Extension and Ulnar deviation > Radial deviation