MPT Anatomy and Kinesiology 1 — Questions and Answers
Question 1: Which muscle is the primary hip flexor and originates from the lumbar vertebrae?
- Rectus femoris
- Iliopsoas (Correct answer)
- Sartorius
- Tensor fasciae latae
Correct answer: Iliopsoas
The iliopsoas, composed of the iliacus and psoas major, is the primary hip flexor. The psoas major originates from the transverse processes and bodies of L1-L5 vertebrae.
The iliopsoas is the strongest hip flexor in the body. The psoas major arises from the anterolateral surfaces of T12-L5 vertebral bodies and their intervertebral discs, while the iliacus originates from the iliac fossa. Both converge on the lesser trochanter of the femur. In physical therapy, weakness of the iliopsoas is commonly assessed in gait analysis and lumbar rehabilitation.
Question 2: The close-packed position of the glenohumeral joint is:
- Arm at 0 degrees abduction
- Full external rotation with 90 degrees abduction (Correct answer)
- 90 degrees flexion with neutral rotation
- Full internal rotation with extension
Correct answer: Full external rotation with 90 degrees abduction
The close-packed position of the glenohumeral joint is full external rotation combined with 90 degrees abduction, where joint surfaces are maximally congruent and ligaments are taut.
In the close-packed position, the articular surfaces are maximally congruent and the joint capsule and ligaments are maximally taut. For the glenohumeral joint this is achieved at full external rotation with abduction (~90 degrees). This position is clinically relevant because it is the most stable position and the joint is most vulnerable to injury when forced out of this position under load. The loose-packed (resting) position is approximately 55 degrees abduction and 30 degrees horizontal adduction.
Question 3: The Q-angle is measured between the line from the ASIS to the patella center and which other line?
- Tibial shaft to the fibular head
- Patella center to the tibial tuberosity (Correct answer)
- Femoral shaft to the patella
- Patella to the medial malleolus
Correct answer: Patella center to the tibial tuberosity
The Q-angle is formed between the line from the ASIS to the patella center and the line from the patella center to the tibial tuberosity. Normal values are approximately 10-15 degrees for men and 15-20 degrees for women.
The quadriceps angle (Q-angle) reflects the net lateral pull of the quadriceps on the patella. An increased Q-angle (>20 degrees) is associated with patellofemoral pain syndrome, patellar instability, and increased risk of ACL injury in females. Physical therapists use Q-angle measurement to guide decisions about patellar taping, orthotic prescription, and VMO strengthening programs.
Question 4: Which nerve innervates the diaphragm?
- Vagus nerve (CN X)
- Phrenic nerve (C3-C5) (Correct answer)
- Long thoracic nerve
- Intercostal nerves T1-T6
Correct answer: Phrenic nerve (C3-C5)
The phrenic nerve (C3, C4, C5) provides motor innervation to the diaphragm. The mnemonic 'C3, 4, 5 keeps the diaphragm alive' is widely used.
The phrenic nerve arises primarily from C4 with contributions from C3 and C5. It descends through the thorax to innervate the diaphragm. Injury at C3 or above results in complete diaphragmatic paralysis requiring mechanical ventilation. Partial sparing at C4-C5 may permit assisted breathing. This is critical knowledge for PTs managing patients with cervical spinal cord injuries, as respiratory function directly determines rehabilitation goals and weaning protocols.
Question 5: The muscle responsible for scapular upward rotation during arm elevation above 90 degrees is:
- Upper trapezius only
- Serratus anterior and lower trapezius force couple (Correct answer)
- Rhomboid major
- Levator scapulae
Correct answer: Serratus anterior and lower trapezius force couple
Scapular upward rotation above 90 degrees requires the serratus anterior and lower trapezius force couple, along with the upper trapezius, to efficiently rotate the glenoid upward.
The scapulohumeral rhythm requires coordinated upward rotation of the scapula. This is achieved primarily by the force couple of serratus anterior (pulling the inferior angle anterolaterally) and lower trapezius (pulling the root of the scapular spine posteromedially downward). Upper trapezius elevates the clavicle contributing to upward rotation. Weakness in serratus anterior (long thoracic nerve palsy) causes winging and impairs overhead function, a common clinical finding.
Question 6: Which of the following joints is classified as a condyloid (ellipsoid) joint?
- Hip joint
- Radiocarpal (wrist) joint (Correct answer)
- Interphalangeal joint
- Sternoclavicular joint
Correct answer: Radiocarpal (wrist) joint
The radiocarpal (wrist) joint is a condyloid joint, allowing flexion/extension and radial/ulnar deviation but no axial rotation.
Condyloid joints have an oval convex surface fitting into an elliptical concavity, permitting flexion-extension and abduction-adduction but preventing axial rotation. The radiocarpal joint is the classic example. The hip is a ball-and-socket joint, the IP joints are hinge joints, and the sternoclavicular joint is a saddle joint. Understanding joint classification helps PTs predict movement restrictions and design appropriate mobilization techniques.
MPT Anatomy and Kinesiology 1
Which muscle is the primary hip flexor and originates from the lumbar vertebrae?