We are all individuals with different body shapes, abilities and needs. In a seated position the shape and support for the upper body is of outmost importance, from the pelvis and up. The goal is to strengthen abilities, prevent impairments and simply improve sitting tolerance over time.
Tall Upper Body
A tall upper body can challenge the postural control and sitting tolerance. Combined with an poor posture, deteriorations on the spine/pelvis may develop rapidly. Trunk stability is necessary to enable a functional and relevant activity level. Also consider the choice of seat cushion, to prevent forward sliding.
Short Upper Body
A Short Upper Body may reduce reach. It can be due to spinal deformation and therefore requires a detailed assessment to obtain the best support. Combined with short leg, the seat depth and foot support also need to be properly adjusted.
Large Upper Body
The upper body can be heavy in relation to the lower body due to abdominal obesity, tall upper body or leg amputation. Abdominal obesity can affect respiration and obstruct hip flexion. A large upper body usually moves the center of gravity forward with high risk for trunk flexion. Allowing the user to lean towards the back support will facilitate trunk extension and respiration.
In a wheelchair this often results in the back support being too wide which can affects trunk stability and arm mobility. In a seated position, a well contoured seat cushion will reduce the enlargement of hip/thigh width. Adding seat width extensions can be an option to create hip space without affecting the back support width.
With broad shoulders the back support may be too narrow. Lowering the back can be an option, but some users need a back support height at the level of the shoulder blades or higher in a tilt and recline wheelchair for comfort and stability.
Posterior Pelvic Tilt
Posterior Pelvic Tilt is a very common reason for poor posture and function. It often results in sliding problems. Allowing a few degrees of supported posterior pelvic tilt from start will stabilize the position and reduce the risk for involuntary progressive pelvic tilt. A well-contoured seat cushion will also help to stabilize the pelvis.
The reason for a leaning posture must be assessed carefully. Is the pelvis involved or does it start with a spinal lateral flexion? Head position? Is there pain involved? An initial assessment will detect pain, pelvic obliquity or other causes that can result in a leaning posture and need to be attended to.
A kyphotic back needs sufficient rear space to allow the user stability and appropriate seat surface. The back support must accommodate and adapt to the individual's back curve. A kyphosis also entail posterior pelvic tilt. To create proper support, a thorough pelvic and spine assessment is necessary. A collapsed trunk combined with normal arm length will also put special demands on the propulsion settings.
Spinal asymmetries can be a result of spasticity, regenerative skeletal disorders or simply poor long-term positioning and must be carefully assessed. Muscle contractions are also common. The goal is to create as much support as possible to prevent further skeletal/muscular impairments. Respiration can be affected and should be given priority.