Anatomy Chapter 3 Flashcards

Questions and Answers

Name the three Cardinal planes and their associated axes.

Mediolateral axis (flexion and extension), Anteroposterior axis (abduction and adduction), Longitudinal axis (internal and external rotation).

Explain why a ball-and-socket joint is so mobile using the shoulder joint as an example.

A ball-and-socket joint allows for a wide range of motion due to its structure, facilitating movements in multiple directions.

Explain how the trunk has such a large range of motion even though each intervertebral joint has only a few degrees of motion.

Movement between adjacent vertebrae is small, but when combined across the whole vertebral column, the trunk's range of motion is substantial.

From an anatomical viewpoint, why is the knee vulnerable to injury?

The knee has poor bony stability in flexion due to the tibial plateau's flattened surface, relying on ligaments for support, which increases injury risk. Signup and view all the answers

Identify the phase of a squat exercise in which quadriceps femoris is acting concentrically and eccentrically.

Concentrically: standing up from a semi-squat position; Eccentrically: going down into the squat position. Signup and view all the answers

Explain in terms of torque how an abdominal crunch is more difficult when the arms are extended overhead compared with folded across the chest.

Extending the arms increases the resistance arm length, resulting in greater resistance torque against which the abdominal muscles have to work. Signup and view all the answers

Using rotational inertia, explain why runners naturally flex the knee of the leg that is swinging forward.

Flexing the knee reduces rotational inertia, requiring less muscular force to swing the leg forward and decreasing local fatigue of the hip flexors. Signup and view all the answers

Why is walking up an incline more challenging for the gluteal muscles than walking on level ground?

Walking up an incline requires greater action from the gluteus maximus and knee extensors to lift the body against gravity. Signup and view all the answers

What type of muscle contractions are involved in exercises performed in water?

Movements performed in water demand concentric muscle contractions. Signup and view all the answers

Study Notes

Cardinal Planes and Axis

Three cardinal planes include sagittal, frontal, and transverse.
Mediolateral axis is linked to the sagittal plane; responsible for flexion and extension movements.
Anteroposterior axis corresponds with the frontal plane; facilitates abduction and adduction movements.
Longitudinal or vertical axis aligns with the transverse plane; allows for internal and external rotational movements.

Mobility of Ball-and-Socket Joints

Glenohumeral joint, a ball-and-socket type, provides extensive mobility due to its spherical head fitting into a rounded socket.
This joint structure allows for rotational movement in multiple planes, facilitating activities such as throwing and overhead movements.

Trunk Range of Motion (ROM)

Individual intervertebral joints allow only a few degrees of motion.
Cumulative movement across the entire vertebral column results in significant trunk ROM.
Trunk movements include flexion, lateral flexion, and rotation, contributing to the overall flexibility and mobility.

Vulnerability of the Knee Joint

Knee joint stability in flexion is compromised due to the flattened tibial plateau.
It relies significantly on ligaments for stability, making it more susceptible to injuries, especially during activities involving twisting or rapid direction changes.

Quadriceps Muscle Action During Squats

During a squat:
- Concentric action occurs when standing up from a squat, as quadriceps work against gravity for hip and knee extension.
- Eccentric action takes place when lowering into a squat, controlling the descent.

Torque in Abdominal Crunches

Arm position affects torque during abdominal crunches; extended arms increase resistance torque.
Holding arms at the sides reduces resistance torque, making the exercise easier.
Overhead arms increase challenge by requiring greater muscle force from abdominal muscles.

Flexed Knee in Running

Runners flex the knee of the swinging leg to minimize rotational inertia around the hip, enhancing efficiency.
A flexed knee requires less muscular force to bring the leg forward, reducing fatigue in hip flexors.
Sprinting benefits from a more rapid recovery limb motion, increasing speed.

Challenges of Walking Up Inclines

Walking or running uphill engages gluteus maximus and knee extensors more significantly due to gravity.
Ankle dorsiflexors activate pre-landing to adapt to incline angles, impacting push-off mechanics.
Increased flexibility in plantar flexors and enhanced strength in dorsiflexors are necessary for effective hill climbing.

Muscle Contractions in Aquatic Exercises

Exercises performed in water primarily utilize concentric muscle contractions.
Water's density offers support and reduces the gravitational load on weight-bearing joints, facilitating movement.

Description

This quiz focuses on the three cardinal planes of the human body and their associated axes. You'll explore the mediolateral, anteroposterior, and longitudinal axes, along with the joint rotations related to each plane. Perfect for students studying anatomy and physiology.