Weight-bearing, the Back & Locomotion (PDF)

Weight-bearing, the Back & Locomotion Body Movement and Function Fiona Cronin [email protected] Learning outcomes By the end of this lecture, you should be able to:  Understand the anatomy of the vertebral column and its curvature  Describe a typical vertebra and list the types and numbers of ve...

Weight-bearing, the Back & Locomotion Body Movement and Function Fiona Cronin [email protected] Learning outcomes By the end of this lecture, you should be able to:  Understand the anatomy of the vertebral column and its curvature  Describe a typical vertebra and list the types and numbers of vertebrae within the vertebral column  Outline the ligaments which help support the vertebral column  Describe the intervertebral joints and the tissues found here  Outline the muscles of the back and the layers of the thoracolumbar fascia  Understand how the different types of movement occur in the vertebral column as a whole and at individual joints  Describe the gait cycle, both walking and running  Describe the typical abnormalities of gait that may be seen in clinical practice  Describe the anatomy and symptoms of a herniated intervertebral disc Recommended reading Abrahams, Peter H. et al. McMinn & Abrahams’ Clinical Atlas of Human Anatomy. Seventh edition. Maryland Heights, Missouri: Elsevier Mosby, 2013. Print Drake, Richard L. Gray’s Anatomy For Students. 4th. ed. Philadelphia: Elsevier, Inc., 2020. Print. Moore, Keith L., Arthur F. Dalley, and A. M. R. Agur. Essential Clinical Anatomy. 4th ed. Philadelphia, Pa.; London: Lippincott Williams & Wilkins, 2011. Print. Netter, Frank H. (Frank Henry). Atlas of Human Anatomy. 5th ed. Philadelphia, Pa.; London: Saunders, 2010. Print. Smith, C., Dilley, A., Mitchell, B. and Drake, R.L., 2017. Gray’s Surface Anatomy and Ultrasound: Gray’s Surface Anatomy and Ultrasound E-Book. Elsevier Health Sciences. Spratt, J., Salkowski, L.R., Loukas, M., Turmezei, T., Weir, J. and Abrahams, P.H., 2020. Weir & Abrahams' Imaging Atlas of Human Anatomy. Elsevier Health Sciences. Back Posterior aspects of the body Mainly vertebrae (other regions such as the base of the skull, pelvis and ribs contribute to it) Function: Support the body’s weight Carry and position the head Help manoeuvre the upper limb Protection of the nervous system Movement Vertebrae 33 vertebrae: 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused), 3-4 coccygeal (often fused) Superior articular process Vertebral Transverse body process Vertebral body Vertebral Pedicle arch Spinous process Lamina Vertebral canal Anatomy of the vertebral column Thoracic region, small gaps Convex curves (kyphosis) Thoracic and sacral regions Concave curves (lordosis) Cervical and lumbar The laminae and spinous process overlap. In the lumbar region, large gaps exist Abnormalities: Lumbar region, Excess lordosis or kyphosis large gaps Scoliosis Abnormal curvature Result from developmental anomalies and/or pathological processes (e.g. osteoporosis) Lordosis: abnormal increase in the lumbar curvature resulting from the anterior rotation of the pelvis. Kyphosis: abnormal increase in the thoracic curvature. Scoliosis Scoliosis is a three-dimensional deformity of the spine affecting the coronal, sagittal, and axial planes. 80% idiopathic. Treatment of patients with idiopathic scoliosis depends on the age of onset and degree of curvature. Ligaments of the vertebra column Supraspinous ligament Anterior longitudinal Anterior longitudinal ligament ligaments: broad, support the intervertebral discs and limit extension. Ligamentum nuchae Posterior longitudinal ligament: narrow, helps Ligamentum flavum Interspinous ligament limit hyperflexion and posterior herniation. Ligamenta flava: between laminae Supraspinous: tips of spinous process, develops into a triangular sheet Posterior longitudinal ligament between the skull and C7 Interspinous: between the spinous processes  Two types: Joints between Symphyses: between the vertebral bodies vertebrae Layer of hyaline cartilage and intervertebral disc Intervertebral disc consists of: Outer annulus fibrosus: a ring of collagen surrounding lamellar fibrocartilage Inner central nucleus pulposus: gelatinous and absorbs compression Synovial (zygapophysial): between articular processes Cervical: slops inferiorly- flexion and extension Thoracic: vertical- limits flexion and allows some rotation Lumbar: curved- limits range of Cervical Thoracic Lumbar movements The motion segment The functional unit of the spine is composed of: Two adjacent vertebrae The intervertebral disc Connecting ligaments Two facets and capsule Movement: Nucleus Pulposus: Functions like a ball- bearing. Allowing the vertebrae to ‘roll’ during flexion, extension and lateral bending Annulus Fibrosis: Functions as a coiled spring holding vertebrae together Normal range of movements in the vertebral column varies with age. Degenerative changes in the annulus fibrous can lead to herniation of nucleus pulposus. Distribution of weight Think of hard Vs soft tissues in the segment Facet joints sustain approx. 30% of weight. 15-30% low back pain emanates from here L5/S1 sustains the highest contact force IV Discs sustain approx. 40% of twisting motion. Only 1-5% of back pain is The vertebral body The facet joints herniated disc and the intervertebral disc transmit approx. 30% of the axial transmit approx. compression 70% of the axial compression Back pain An immense health problem. Could be from: Fibroskeletal structures: periosteum, ligaments, and anuli fibrosi of IV discs Meninges: coverings of the spinal cord Synovial joints: capsules of the zygapophysial joints Affects 60-80% of people throughout their lifetime. Muscles: intrinsic muscles of the By 2050, a 36.4% rise in low back back pain cases is projected 98% recovery: 6-12 weeks Nervous tissue: spinal nerves or Only 14% recover within 1 month/yr, with nerve roots exiting the IV foramina disability Spinal nerves Spinal cord extends from foramen magnum to L1-L2 in adults Till L3 in neonates Nerves extend beyond the end of the spinal cord as cauda equina. There are 31 spinal nerves C1-C7 emerge above their respective vertebrae C8: emerges above T1 From T1-onward: emerge below their respective vertebrae Herniated disc Herniation or protrusion of the gelatinous nucleus pulposus into or through the anulus fibrosus can compress the spinal cord or spinal nerves Posterolateral herniation is most common in the lumbar region Approx. 95% of protrusions occur at the L4–L5 or L5–S1 levels. In older patients, the nerve roots are more likely to be compressed by increased ossification (osteophytes) of the IV foramen as they exit. Herniation L3/L4: Anterior thigh pain, weak quad, absent tendon reflex, femoral stretch + Herniation L4/5: Leg pain? weak movement, sciatic stretch + Herniation L5/S1: Pain, weakness, absent calcaneal tendon reflex, sciatic stretch + Stretch tests Sciatic Femoral Supine Prone Leg raise Flex knee Ankle Extend hip dorsiflexion Pain radiating down the back of the leg to Pain radiating from the back down the front the foot (increased by dorsiflexing the of the leg to the knee indicates L2/L3/L4 ankle) indicates L4/L5/S1 nerve root tension nerve root tension Aging With increasing age, the normally gelatinous nucleus pulposus becomes dehydrated and degenerates. This gradually leads to progressive loss of the height of the intervertebral disk space. This results in abnormal loading of the facet joints with the development of facet arthritis, osteophyte formation (heterotopic bone growth), greater stress on adjacent ligaments and muscles, and thickening of the ligamentum flavum. Cauda Equina Syndrome Causes: Midline (large) herniation Trauma, tumour, haematoma Rare (but common enough) Symptoms: Bilateral LL weakness Numbness: perianal numbness Incontinence-impairment of bladder, bowel or sexual function. Urgent surgical referral: left untreated, can lead to devastating long-term complications such as incontinence of bladder or bowel, loss of lower limb function and sexual dysfunction. Superficial muscles of the back Levator scapulae (extrinsic)  C1-C4 to scapula  Elevates the scapula Trapezius  Dorsal scapular nerve/C3  Skull and nuchal ligament to clavicle and scapula. Rhomboid minor  Elevates, retracts/adducts, depresses and rotates  C7-T1 to scapula scapula.  Adducts and elevates the  Accessory nerve scapula  Dorsal scapular nerve Latissimus dorsi  Spinous process of T7-L5 to the intertubercular sulcus Rhomboid major  Extends, adducts and medially  T2-T5 to scapula rotates the humerus.  Adducts and elevates the scapula  Thoracodorsal nerve  Dorsal scapular nerve Deep muscles of the back (intrinsic) Splenius muscles (capitis and Transversospin cervicis) al muscles Erector spinae  Function in maintaining posture and controlling the column Movements of the Back  Thoracolumbar fascia Covers the deep muscles of the back and trunk Covers the anterior surface of the quadratus lumborum muscle. Forms the lateral arcuate ligament of the diaphragm (sup). Attached to the tips of the Thick and is attached to the transverse processes of the spinous processes lumbar vertebrae (medially), iliac (lumbar+sacral). Extends crest (inf), rib 12 (sup). laterally to cover the erector Gait-walking Locomotion is a complex function. Two phases: Swing phase (40%): begins after the push-off and ends with a heel strike. Stance phase (60%): starts with a heel strike and ends with a push-off. The gait cycle consists of one swing and one stance phase for ONE LIMB. Gait-running Does NOT have a period of double support. It has alternating periods of single support, separated by a double float phase/flight phase (when both feet are airborne). Stance phase shortened, swing is longer Gait analysis Can be helpful in initial diagnosis. E.g. Hemiplegic, antalgic, Trendelenberg, high-stepping (foot- drop), festination (Parkinson’s) Gait examination video (For information ONLY)  Thank you Acknowledgement: Dr Sara Sulaiman